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61.
We consider a simple model consisting of particles with four bonding sites ("patches"), two of type A and two of type B, on the square lattice, and investigate its global phase behavior by simulations and theory. We set the interaction between B patches to zero and calculate the phase diagram as the ratio between the AB and the AA interactions, ε(AB)*, varies. In line with previous work, on three-dimensional off-lattice models, we show that the liquid-vapor phase diagram exhibits a re-entrant or "pinched" shape for the same range of ε(AB)*, suggesting that the ratio of the energy scales--and the corresponding empty fluid regime--is independent of the dimensionality of the system and of the lattice structure. In addition, the model exhibits an order-disorder transition that is ferromagnetic in the re-entrant regime. The use of low-dimensional lattice models allows the simulation of sufficiently large systems to establish the nature of the liquid-vapor critical points and to describe the structure of the liquid phase in the empty fluid regime, where the size of the "voids" increases as the temperature decreases. We have found that the liquid-vapor critical point is in the 2D Ising universality class, with a scaling region that decreases rapidly as the temperature decreases. The results of simulations and theoretical analysis suggest that the line of order-disorder transitions intersects the condensation line at a multi-critical point at zero temperature and density, for patchy particle models with a re-entrant, empty fluid, regime. 相似文献
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63.
T Madhusoodhanan Samit Mandal MP Sathyavathiamma Ramani NG Puttaswamy TS Mudhole A Mandal DK Avasthi R Shyam SK Datta 《Pramana》1999,53(3):541-544
The inclusive and exclusive measurements were carried out for 7Li projectile breakup on 27Al target at 48 MeV. In the inclusive data we have observed a broad peak around the beam velocity for alphas and tritons.
The exclusive data for alpha-triton coincidences show good agreement with the post-form DWBA theory of breakup reactions. 相似文献
64.
从含4,4'-二吡啶胺结构单元的双(二吡啶胺) 桥联配体出发,采用溶剂热法合成了两个结构新颖的配位聚合物:[CdL1Br2]n?7.5nH2O (L1 = N,N,N′,N′-四(4-吡啶)-1,4-苯二胺) (1)和[Cu2L2(μ1,1,3-SCN)2]n?nMeOH (L2 = N,N-二(2-吡啶)-N',N'-二(4-吡啶)-1,4-苯二胺) (2),对它们进行了元素分析、红外光谱等表征,并用X-射线单晶衍射测定了其晶体结构。单晶测试结果显示,配合物1中配体L1的四个吡啶N原子均参与配位,桥联了4个Cd原子,每个Cd原子与四个吡啶 N 原子和两个溴配位,形成六配位的八面体构型。通过这些配位作用,最终形成包含 Kagome 结构的三维超分子网络。配合物2 是由一维柱状 {Cu(SCN)}n 链通过 L2 桥联生成的二维结构。有趣的是,L2中具有螯合能力的2,2'-二吡啶胺单元并未参与配位,只有4,4'-二吡啶胺单元中的两个吡啶N原子分别与一个 Cu(I) 配位,连接了相邻两条平行的{Cu(SCN)}n 链,生成二维结构。 相似文献
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66.
In this paper,we study and analyze the regularized least squares for function-on-function regression model.In our model,both the predictors(input data)and respo... 相似文献
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68.
We propose an efficient algorithm to perform Monte Carlo simulations of dense systems using multiple particle moves. The method is intended to be used in the atomistic simulation of complex systems, where the computing requirements for a single simulation run make advisable the use of parallel computing. The algorithm is based on the use of steps in which all the particle positions of the system are perturbed simultaneously. A division of the system in clusters of particles is performed, using a bonding criterion which makes feasible that the acceptance or rejection of the new particle coordinates can be carried out independently for each cluster. 相似文献
69.
Let k, m be two positive integers with m ≤ k and let F be a family of zero-free meromorphic functions in a domain D, let h(z) ≡ 0 be a meromorphic function in D with all poles of h has multiplicity at most m. If, for each f ∈ F, f(k)(z) = h(z) has at most k- m distinct roots(ignoring multiplicity) in D, then F is normal in D. This extends the results due to Chang[1], Gu[3], Yang[11]and Deng[1]etc. 相似文献
70.
The molecule of 4-tricyanovinyl-N,N-diethylaniline is disordered about an axis that is close to the axis passing through the 1,4-carbon atoms. The disorder is a 1:1 type of disorder that involves only part of the molecule as the diethylamino substitutent and the three nitrogen atoms of the tricyanovinyl substituent are ordered. The treatment of the nearly ‘whole-molecule disorder’ by employing a small number of restraints is described. Crystal data: C15H14N4, triclinic, P , a = 7.1996(5), b = 7.7232(5), c = 12.4171(8) , α = 99.350(1), β = 94.647(1), γ = 103.312(1)o and V = 657.90(8) 3 at –173 K. 相似文献